Polished rod clamp



Dec. 17, 1963 l. c. NOURSE POLISHED ROD CLAMP Filed April 19, 1962 IRA C. N O URSE Lay VENTOR.

ATTORNEY United States Patent 3,114,188 POLISHED ROD CLAMP Ira C. Nourse, 1157 Victoria St., Abilene, Tex. Filed Apr. 19, 1962, Ser. No. 188,731 1 Claim. (Cl. 24-249) This invention relates to polished rod clamps for use n the repair and servicing of oil well pumps, and has for its object on improved clamp construction which has a more powerful grip on the polished rod yet cannot damage the surface of the rod.

In deep oil wells the weigh-t of the sucker rod string is heavy, and this weight is carried by the polished rod at the top of the string by a bridle which runs over the mulehead on the end of the walking beam of a pumping unit. The invention is also applicable to other types of pumping 'llllltS, for example, hydraulic units, connected with the upper ends of polished rods. In case of the need to replace any of the elements on which the weight is suspended, the only way to keep the weight of the string off of the bottom of the pump is to place a clamp on the part of the polished rod above the stufiing box and let the clamp bear on the top of the stuifing "box or temporary means, such as a sleeve designed for that purpose, thus transferring the weight to the casing head.

It is essential that a clamp used for this purpose shall have a grip greater than the weight of the string. It is essential that the gripping surface of the clamp does not damage the surface of the polished rod.

It is a further object of the invention to provide a polished rod clamp for use in conjunction with a pump rod jack such as is described in my previous Patents No. 2,645,454, to hold the polished rod in position while the jack is being attached or removed.

A further object of the invention is to provide a polished rod clamp which will exert a minimum of eccentric forces on the polished rod while carrying the weight of the sucker rods and pump.

Since polished rods are manufactured to extremely close tolerances it is possible to make a clampwith a bore which exactly matches every standard size of rod, and if this bore is finely machined and polished to match the rod onwhich it is to be used it will exert a powerful pressure on the rod for substantially its entire contact area without pitting or denting the surface of the rod.

Other novel features of the invention will become apparent from the following description and the accompanying drawings, in which:

FIGURE "1 is a top view of one embodiment of the invention.

FIGURE 2 is a side view of FIGURE 1.

FIGURE 3 is a vertical longitudinal sectional View of the clamp.

FIGURE 4 is an elevational view of the clamp in use showing part of the polished rod and easing head.

FIGURE 5 is a perspective view of a second embodiment of the clamp.

The clamp consists essentially of a pair of hinged jaws and a bolt. A front jaw 11 and a rear jaw 12 encompass a vertical bore 13, approximately one half of which 14 extends into the front jaw 11 and approximat 1y one-half of which 15 extends into the rear jaw 12. Corresponding ends of the jaws are fitted together to form a hinge 16, the respective hinge bearings 17 and 18 having "Ice a structural cross section roughly equivalent to that of each jaw adjacent the bore 13. A hinge pin 19 of hardened steel is secured by a press fit in the center hinge bearing 18 and turns smoothly in the outer hinge bearing 17. The end of the jaw 11 opposite the hinge 16 is provided with a bolt hole 20 having its center approximately the same, or greater than, the distance from the bore '13 as the center of the hinge pin 19. The bolt hole 20 has a rectangular recess 21 at its outer end and its inner end is arculately formed at 22 as shown in FIGURE 1. The opposite jaw 12 has a slot 23 in line with the bolt hole 20 and which slot extends to the end of the jaw "12 as shown in FIGURE 4. A square head, high strength bolt 24, with a nut 25 and a washer 26, is loosely fitted in the hole 20 and the slot 23, and which bolt is long enough to swing outwardly as shown in FIGURE 1 to allow the clamp to open without removing the nut.

FIGURE 4 illustrates a typical application of the invention and shows the casing head 27, the tubing head 28, and the stufling box 29. The clamp 10 is tightened around the polished rod and the full weight of the sucker rod string, not shown, is carried by the clamp bearing on top or the stufiing box 29. It is a common procedure to supply a temporary sleeve or other support, not shown, to transmit the weight of the string to the casing head. The top and bottom faces 31 and =32 of the clamp 10 are parallel to each other and perpendicular to the bore 13 to prevent any eccentric loading on the polished rod 30. If the well is so deep that one clamp 10 may be inadequate to carry the load, a second clamp may 'be fitted tightly against it as shown by the dotted lines, FIGURE 1, thus increasing the holding capacity.

An important feature of the invention is the proportioning of the jaws 11 and 12 in which the cross sectional area of material transversely of the bore '13 at 33 is sub stantially less than in the adjacent areas at 34. The inner faces 35 of the jaws 11 and 12 are dimensional to leave a space therebetween when the bore 13 is positioned abound the polished rod 30'. When the bolt 24 is tightened the flexing action of the clamp i011 the rod 341* provides a powerful uniform pressure of the inner surfiaces of the bore 13 substantially around the outer surface of the polished rod 30. It has been proven by laboratory tests that this design results in a substantial increase in holding power over clamps in which the cross section of material at 33 is equal to or greater than the cross section of material at 34. It has also been demonstrated that a continuous smooth surface on the inside of the bore holds better than a surface comprised of rings or ridges.

FIGURE 5 illustrates a two bolt adaptation of the invention which includes all the features herein described and is directed to a clamp 10a of increased holding capacity by reason of its longer bore 13a in jaws 11a and 12a of increased height. In addition to the two bolts 24a, one above the other, there are additional interfitting ears 17a and 18a for receiving a longer pin 19a.

The invention is not limited to the exemplary construc tion herein shown and described, but may be made in various ways within the scope of the appended claim.

What is claimed is:

A polished rod clamp comprising an elongate pair of jaws of flexible steel, a hinge connecting corresponding ends of said jaws, said jaws being in substantially close parallel spaced position relative to each other when in closed position, a bolt loosely received in substantially aligned openings in the ends of said jaws oppcsi-te said hinge and having its axis perpendicular to the axis of said hinge, the diameters of said openings being larger than the diameter of said bolt, and substantially halfround recesses in opposing surfaces of said jaws to provide :1 polished rod receiving here, the surfaces of said bore being substantially as polished as the surface of the polished rod to be received therein, the axis of said bore being parallel with the axis of said hinge end located 10 2,934,803

4 closer to said hinge than to said bolt, said jaws being sufficiently thin at said bore to permit flexing of said jaws when said bolt is tightened.

References Cited in the file of this patent UNITED STATES PATENTS 2,260,544 Stanley Out. 28, 1941 2,346,859 Mills Apr. 18, 1944 2,645,454 Nourse July 14, 1953 Allen May 3, 1960 

